利用地震矩张量初步分析断裂带的运动学特征
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摘要
文中探讨了利用地震矩张量反演断裂形变带运动学参数的方法,并将其应用于鲜水河断裂带和汾渭断裂带现今运动学特征的研究。结果表明,鲜水河断裂带呈N16°W方向拉伸,N74°E方向压缩,并且以10.9mm/a的速率发生左旋剪切运动;汾渭断裂带呈N20°W方向拉伸,N78°E方向压缩,并且以0.24mm/a的速率发生右旋剪切运动。
In this paper, the method for inversing the kinematics parameters of a fault zone from seismic moment tensors is discussed and applied to the study of the present kinematics characteristics of Xianshuihe Fault zone and Fenwei Fault zone. The results show that the Xianshuihe Fault zone extends in the direction of N16°W and is compressed in the direction of N74°E. The average sinistral motion rate is about 10.9 mm/a. The Fenwei Fault zone extends in N20°W and is compressed in N78°W direction. The average dextral motion rate is about 0.24mm/a. Comparing the results mentioned above to the geological information and the GPS results, it is found that the motion directions of fracture zone are basically agreeable, but the slip rate is less than that of the latter two, especially in the Fenwei Fault zone. Three reasons may explain this phenomenon, firstly, the time when the data are collected is different; secondly, all strain energy produced by geological body is assumed to be released by means of the stick slip, instead of creep-slip of the fault; and thirdly there were totally 14 earthquakes of magnitude greater that 5 occurring in the sampled time period, among which there was only one earthquake of maximum over 6 and the largest event is M 6.2. The motion rate of the fault zone calculated from seismic moment tensors is less than the average rate drawn by geological information. This shows that the strain energy of the geological body has not been released completely. So there exists high seismic risk. In addition, the motion rate of the Fenwei Fault zone is less than that of the Xianshuihe Fault zone, indicating that the level of seismicity and the energy released by earthquake of the former is less than that of the latter.
In this paper, the method for inversing the kinematics parameters of a fault zone from seismic moment tensors is discussed and applied to the study of the present kinematics characteristics of Xianshuihe Fault zone and Fenwei Fault zone. The results show that the Xianshuihe Fault zone extends in the direction of N16°W and is compressed in the direction of N74°E. The average sinistral motion rate is about 10.9 mm/a. The Fenwei Fault zone extends in N20°W and is compressed in N78°W direction. The average dextral motion rate is about 0.24mm/a. Comparing the results mentioned above to the geological information and the GPS results, it is found that the motion directions of fracture zone are basically agreeable, but the slip rate is less than that of the latter two, especially in the Fenwei Fault zone. Three reasons may explain this phenomenon, firstly, the time when the data are collected is different; secondly, all strain energy produced by geological body is assumed to be released by means of the stick slip, instead of creep-slip of the fault; and thirdly there were totally 14 earthquakes of magnitude greater that 5 occurring in the sampled time period, among which there was only one earthquake of maximum over 6 and the largest event is M 6.2. The motion rate of the fault zone calculated from seismic moment tensors is less than the average rate drawn by geological information. This shows that the strain energy of the geological body has not been released completely. So there exists high seismic risk. In addition, the motion rate of the Fenwei Fault zone is less than that of the Xianshuihe Fault zone, indicating that the level of seismicity and the energy released by earthquake of the former is less than that of the latter.
引文
①http:∥www.seismology.harvard.edu/cgi bin/CMT2/form?itype=ymd&yr=1999&mo=1&day=1&oyr=
1&omo=1&oday=1&jyr=1976&jday=1&ojyr=1976&ojday=1&otype=nd&nday=365&lmw=0&umw=10&lms=
0&ums=10&lmb=0&umb=10&llat=34&ulat=42&llon=106&ulon=116&lhd=0&uhd=1000<s=-9999&uts=9999&lpel=0&upel=90&lpe2=0&upe2=90&list=0
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刘杰,郑斯华,康英,等.2004.利用P波和S波的初动和振幅比计算中小地震的震源机制解[J].地震,24(1):19—26.LIUJie,ZHENGSi hua,KANGYing,etal.2004.Thefocalmechanismdeterminationsofmoderate smallearthquakes usingthefirstmotionandamplituderatioofPandSwave[J].Earthquake,24(1):19—26(inChinese).
吕江宁,沈正康,王敏.2003.川滇地区现代地壳运动速率场和活动块体模型研究[J].地震地质,25(4):543—554.L櫣Jiang ning,SHENZheng kang,WANGMin.2003.Contemporarycrustaldeformationandactivetectonicblockmod eloftheSichuan Yunnanregion,China[J].SeismologyandGeology,25(4):543—554(inChinese).
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王秀文,赵文星,杨国华.2004.山西地堑系的最新水平运动[J].山西地震,1:20—24.WANGXu wen,ZHAOWen xing,YANGGuo hua.2004.ThelatesthorizontalmovementofShanxiGrabensystem[J].EarthquakeResearchinShanxi,1:20—24(inChinese).
汪素云,许忠淮,俞言祥,等.1997.我国大陆应力场特征和强震关系的分区研究[A].见:国家地震局科技发展司编.中国大陆2005年前强震危险性预测研究.北京:地震出版社.110—116.WANGShu yun,XUZhong huai,YUYan xiang,etal.1997.Thezoningstudyofrelationshipbetweenthefeatureof strainfieldinChinesemainlandandstrongearthquakes[A].In:DepartmentResearchandDevelopment,SSB(ed).Earthquakeriskpredictionbefore2005inChinesemainland.SeismologicalPress,Beijing.110—116(in Chinese).
王卫东.2002.泾阳MS4.8地震的发震构造与破裂特征[J].地震学报,24(5):552—555.WANGWei dong.2002.SeismogenicstructureandrupturecharacteristicsoftheMS4.8Jingyangearthquake[J].ActaSeismologicaSinica,24(5):552—555(inChinese).
王炎,刁桂苓,张四昌,等.2002.1999年山西大同MS5.6地震的震源断层[J].中国地震,18(1):96—101.WANGYan,DIAOGui ling,ZHANGSi chang,etal.2002.ThefocalfaultoftheMS5.6Datongearthquakeof1999in ShanxiProvince[J].EarthquakeResearchinChina,18(1):96—101(inChinese).
谢智,刘尧兴,胡卫建,等.2002.河南及邻区地震的震源机制[J].西北地震学报,24(3):283—286.XIEZhi,LIUYao xing,HUWei jian,etal.2002.ThefocalmechanismofearthquakeinHenananditsadjacentregion[J].NorthwesternSeismologicalJournal,24(3):283—286(inChinese).
徐锡伟,邓起东,董瑞树,等.1992.山西地堑系强震的活动规律和危险区段的研究[J].地震地质,14(4):305—316.XUXi Wei,DENGQi dong,DONGRui shu,etal.1992.Studyonstrongearthquakeactivityandriskareasinthe ShanxiGrabensystem[J].SeismologyandGeology,14(4):305—316(inChinese).
徐锡伟,闻学泽,郑荣章,等.2003.川滇地区活动块体最新构造变动样式及其动力来源[J].中国科学(D辑),33(S1):151—162.XUXi wei,WENXue ze,ZHENGRong zhang,etal.2003.Patternoflatesttectonicmotionanditsdynamicsforac tiveblocksinSichuan Yunnanregion,China[J].ScienceinChina(SerD),33(S1):151—162(inChinese).
杨国华,谢觉民,韩月萍.2001.华北主要构造单元及边界带现今水平形变与运动机制[J].地球物理学报,(5):645—653.YANGGuo hua,XIEJue min,HANYue ping.2001.Currenthorizontaldeformationandkinematicmechanismofm jortectonicunitsandboundaryzonesinNorthChina[J].ChineseJournalofGeophysics,44(5):645—653(Chinese).
杨国华,王敏,韩月萍,等.2002.山西断裂带活动趋势与动态特征[J].中国地震,18(2):148—156.YANGGuo hua,WANGMin,HANYue ping,etal.2002.ThemovementoftrendanddynamiccharacterinShanxi Faultzone[J].EarthquakeResearchinChina,18(2):148—156(inChinese).
张世民,谢富仁.2001.鲜水河-小江断裂带7级以上强震构造区的划分及其构造地貌特征[J].地震学报,23(1):36—44.ZHANGShi min,XIEFu ren.2001.Seismo tectonicdivisionsofstrongearthquakes(MS≥7.0)andtheirtectonicge omorphologyalongXianshuihe XiaojiangFaultzone[J].ActaSeismologicaSinica,23(1):36—44(inChinese).
ConstantinosBPapazachos,AnastasiaAKiratzi.1992.Aformulationforreliableestimationofactivecrustaldeforma tionanditsapplicationtocentralGreece[J].GeophysJInt,111:424—432.
JamesJackson,DanMcKenzie.1988.Therelationshipbetweenplatemotionsandseismicmomenttensorsandtherates ofactivedeformationintheMediterraneanandMiddleEast[J].GeophysicalJournal,93:45—73.
1&omo=1&oday=1&jyr=1976&jday=1&ojyr=1976&ojday=1&otype=nd&nday=365&lmw=0&umw=10&lms=
0&ums=10&lmb=0&umb=10&llat=34&ulat=42&llon=106&ulon=116&lhd=0&uhd=1000<s=-9999&uts=9999&lpel=0&upel=90&lpe2=0&upe2=90&list=0
国家地震局鄂尔多斯周缘活动断裂系课题组.1988.鄂尔多斯周缘活动断裂系[M].北京:地震出版社.162—173.TheResearchGrouponActiveFaultSystemaroundOrdosMassif,StateSeismologicalBureau.1988.ActiveFaultSys temaroundOrdosMassif[M].SeismologicalPress,Beijing.162—173(inChinese).
黄立人,王敏.2000.中国大陆现今地壳水平运动[J].地震学报,22(3):257—262.HUANGLi ren,WANGMin.2000.RecentcrustalhorizontalmovementinChinesemainland[J].ActaSeismologica Sinica,22(3):257—262(inChinese).
李天诏.1996.鲜水河活动断裂带地震地质研究的新进展[J].国际地震动态,7:16—18.LITian zhao.1996.NewprogressinseismogeologicalresearchontheactiveXianshuiheFaultzone[J].RecentDe velopmentsinWorldSeismology,7:16—18(inChinese).
刘杰,郑斯华,康英,等.2004.利用P波和S波的初动和振幅比计算中小地震的震源机制解[J].地震,24(1):19—26.LIUJie,ZHENGSi hua,KANGYing,etal.2004.Thefocalmechanismdeterminationsofmoderate smallearthquakes usingthefirstmotionandamplituderatioofPandSwave[J].Earthquake,24(1):19—26(inChinese).
吕江宁,沈正康,王敏.2003.川滇地区现代地壳运动速率场和活动块体模型研究[J].地震地质,25(4):543—554.L櫣Jiang ning,SHENZheng kang,WANGMin.2003.Contemporarycrustaldeformationandactivetectonicblockmod eloftheSichuan Yunnanregion,China[J].SeismologyandGeology,25(4):543—554(inChinese).
马淑田,陈会忠,王松,等.1998.1998年1月10日河北省张北-尚义MS6.2地震震源机制的初步研究[J].地球物理学报,41(5):724—728.MAShu tian,CHENHui zhong,WANGSong,etal.1998.ApreliminarystudyoffocalmechanismofMS6.2earth quakeonJanuary10,1998inZhangbei Shangyiregion[J].ActaGeophysicaSinica,41(5):724—728(inChi nese).
孙建中,施顺英,周硕愚,等.1994.利用地震矩张量反演鲜水河断裂带现今运动学特征[J].地壳形变与地震,
14(4):9—15.SUNJian zhong,SHIShun ying,ZHOUShuo yu,etal.1994.Inversionofthepresentkinematiccharacteristicsof XianshuiheFaultzonefromseismicmomenttensor[J].CrustalDeformationandEarthquake,14(4):9—15(in Chinese).
王秀文,赵文星,杨国华.2004.山西地堑系的最新水平运动[J].山西地震,1:20—24.WANGXu wen,ZHAOWen xing,YANGGuo hua.2004.ThelatesthorizontalmovementofShanxiGrabensystem[J].EarthquakeResearchinShanxi,1:20—24(inChinese).
汪素云,许忠淮,俞言祥,等.1997.我国大陆应力场特征和强震关系的分区研究[A].见:国家地震局科技发展司编.中国大陆2005年前强震危险性预测研究.北京:地震出版社.110—116.WANGShu yun,XUZhong huai,YUYan xiang,etal.1997.Thezoningstudyofrelationshipbetweenthefeatureof strainfieldinChinesemainlandandstrongearthquakes[A].In:DepartmentResearchandDevelopment,SSB(ed).Earthquakeriskpredictionbefore2005inChinesemainland.SeismologicalPress,Beijing.110—116(in Chinese).
王卫东.2002.泾阳MS4.8地震的发震构造与破裂特征[J].地震学报,24(5):552—555.WANGWei dong.2002.SeismogenicstructureandrupturecharacteristicsoftheMS4.8Jingyangearthquake[J].ActaSeismologicaSinica,24(5):552—555(inChinese).
王炎,刁桂苓,张四昌,等.2002.1999年山西大同MS5.6地震的震源断层[J].中国地震,18(1):96—101.WANGYan,DIAOGui ling,ZHANGSi chang,etal.2002.ThefocalfaultoftheMS5.6Datongearthquakeof1999in ShanxiProvince[J].EarthquakeResearchinChina,18(1):96—101(inChinese).
谢智,刘尧兴,胡卫建,等.2002.河南及邻区地震的震源机制[J].西北地震学报,24(3):283—286.XIEZhi,LIUYao xing,HUWei jian,etal.2002.ThefocalmechanismofearthquakeinHenananditsadjacentregion[J].NorthwesternSeismologicalJournal,24(3):283—286(inChinese).
徐锡伟,邓起东,董瑞树,等.1992.山西地堑系强震的活动规律和危险区段的研究[J].地震地质,14(4):305—316.XUXi Wei,DENGQi dong,DONGRui shu,etal.1992.Studyonstrongearthquakeactivityandriskareasinthe ShanxiGrabensystem[J].SeismologyandGeology,14(4):305—316(inChinese).
徐锡伟,闻学泽,郑荣章,等.2003.川滇地区活动块体最新构造变动样式及其动力来源[J].中国科学(D辑),33(S1):151—162.XUXi wei,WENXue ze,ZHENGRong zhang,etal.2003.Patternoflatesttectonicmotionanditsdynamicsforac tiveblocksinSichuan Yunnanregion,China[J].ScienceinChina(SerD),33(S1):151—162(inChinese).
杨国华,谢觉民,韩月萍.2001.华北主要构造单元及边界带现今水平形变与运动机制[J].地球物理学报,(5):645—653.YANGGuo hua,XIEJue min,HANYue ping.2001.Currenthorizontaldeformationandkinematicmechanismofm jortectonicunitsandboundaryzonesinNorthChina[J].ChineseJournalofGeophysics,44(5):645—653(Chinese).
杨国华,王敏,韩月萍,等.2002.山西断裂带活动趋势与动态特征[J].中国地震,18(2):148—156.YANGGuo hua,WANGMin,HANYue ping,etal.2002.ThemovementoftrendanddynamiccharacterinShanxi Faultzone[J].EarthquakeResearchinChina,18(2):148—156(inChinese).
张世民,谢富仁.2001.鲜水河-小江断裂带7级以上强震构造区的划分及其构造地貌特征[J].地震学报,23(1):36—44.ZHANGShi min,XIEFu ren.2001.Seismo tectonicdivisionsofstrongearthquakes(MS≥7.0)andtheirtectonicge omorphologyalongXianshuihe XiaojiangFaultzone[J].ActaSeismologicaSinica,23(1):36—44(inChinese).
ConstantinosBPapazachos,AnastasiaAKiratzi.1992.Aformulationforreliableestimationofactivecrustaldeforma tionanditsapplicationtocentralGreece[J].GeophysJInt,111:424—432.
JamesJackson,DanMcKenzie.1988.Therelationshipbetweenplatemotionsandseismicmomenttensorsandtherates ofactivedeformationintheMediterraneanandMiddleEast[J].GeophysicalJournal,93:45—73.
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